WM 10 10581 - phone is not responsive

I've updated to Windows 10 Mobile 10581 on my Lumia 1020 (RM-875), did hard reset after an update so it should have been clean update. Afterwards, I've installed all my apps, copied my music etc and have been living happy with my device.

Yesterday, I connected my phone to my PC via USB to copy some photos from the device. During this process, my phone rebooted itself and then my phone acted strangely. It is really strange, as:

Battery: shows empty with 0%, and charging icon is blinkingback/start/search buttons are not wokringStart screen is blankAction Center - I can't open anything except WiFi, Airplane Mode, Cellular, Mobile Hotspot.
Only Flashlight, Volume keys and Lock keys are working